jamovi_set_data · jamovi MCP: Risk & Policy

WHAT IT DOES

What jamovi_set_data does on jamovi MCP

AI agents use jamovi_set_data to create or update resources in jamovi MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your jamovi MCP environment.

WHY IT NEEDS A POLICY

Why jamovi_set_data needs a policy

This tool modifies data reversibly (a cell value can be changed again), making it a Write operation rather than Read (which would only retrieve data) or Destructive (which would be irreversible deletion). The severity is medium because modifying dataset cells can alter analysis results and model conclusions, but the impact is limited to a single cell at a time and is reversible.

From the tool's definition The tool 'jamovi_set_data' is described as 'Set a single cell value in the dataset.' This explicitly performs a data modification operation—specifically, it writes a new value to a cell in an active dataset.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

jamovi_set_data Rate-limited

jamovi_set_data stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "jamovi_set_data": {
      "limits": [
        {
          "counter": "jamovi_set_data_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches jamovi MCP, so you can run agents against it safely.

FAQ

Questions about jamovi_set_data

What does the jamovi_set_data tool do? +

Set a single cell value in the dataset. It is categorised as a Write tool in the jamovi MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on jamovi_set_data? +

Register the jamovi MCP server in PolicyLayer and add a rule for jamovi_set_data: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches jamovi MCP. Nothing to install.

What risk level is jamovi_set_data? +

jamovi_set_data is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit jamovi_set_data? +

Yes. Add a rate_limit block to the jamovi_set_data rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block jamovi_set_data completely? +

Set action: deny in the PolicyLayer policy for jamovi_set_data. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides jamovi_set_data? +

jamovi_set_data is provided by the jamovi MCP server (yjm110517/jamovi-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.